Process of reducing sodium compounds.



Patented May 7, mm.

A. H, COWLES. PROCESS OF REDUCING SODIUM COMPOUNDS.

(AppXication filed July 20, 1895.)

(No Model.)

UNITED STATES PATENT OFFICE.

ALFRED I-I. COWVLES, OF CLEVELAND, OHIO, ASSIGNOR TO THE ELECTRIC SMELTING AND ALUMINUM COMPANY, OF ILLINOIS.

PROCESS OF REDUCING SODIUM COMPOUNDS.

SPECIFICATION forming part of Letters Patent No. 673,761, dated May 7, 1901.

Application filed July 20, 1895- Serial No. 557,172. (No specimens.)

To aZZ whom it may concern: C is the carbon electrode, attached to a rod Be it known that I, ALFRED H. COWLES, a C by means of an intermediate metallic plug citizen of theUnited States, residing at Cleveor plugs c and having suitable connection land, in the county of Cuyahoga and State of with the electric circuit generated by dynamo 5 Ohio, have invented certain new and useful or other suitable generator of electricity,

Improvements in Processes of Reducing Sowhich may produce either continuous or aldium Compounds; and Ido hereby declare the ternated current. following to be a full, clear, and exact descrip- D represents the carbon lining and carbon tion 0ftheinvention,such as willenable others hearth of the furnace. Inclosing the carbon 1o skilled in the art to which it appertains to wall or lining is a. metallic double-Walled make and use the same. jacket d, the inner wall of which, in contact The object of the present process is to siwith the carbon lining of the furnace, is permultaneously reduce sodium compounds of forated with numerous openings, through refractory oXids non-reducible practically by which the gases and vapor from the furnace 15 ordinary fiery processes with carbon, the purmay enter the space between the wall of the pose being to obtain separately the sodium jacket (1, which forms a condenser in which and the base of the oXid, either as metal, carthe metallic vapors will be condensed, as bid, or alloy. hereinafter described. Outside of the jacket In the application of the process herein de (1 is a water-jacket a, surrounding the same 2o scribed I make use of an electric furnace, not and provided with suitable water inlet and necessarily limited as to type,but which must, outlet pipes, the office of said" jacket being to of course, be provided with a suitable conmaintain the temperature of the condensingdenser. I jacket d at the proper temperature to effect In the drawings hereto annexed I have the condensation of the sodium vapors dis- 25' shown a furnace covered by my applications charged thereinto. An exhaust-pipe Fopens filed November 24:, 1899, Serial No. 738,201, from the upper part of the jacket cl, through and August 30, 1900, Serial No. 28,606, both which the carbonic oXid generated in the of which are divisionals of this application, operation is passed off, assisted, if need be, by well adapted to the carrying out of the proca suction-blower; or equivalent device, (not 8.)

3o ess hereinafter described and which form I shown,) which may be attached to the pipe F.

prefer to use, it being understood that a dif- At the bottom of the furnace-chamber a tapferent form of furnace may be successfully hole K is provided, and at the bottom of the used if it be so constructed that the interior jacket da discharge-pipeLfor drawing oi the temperature throughout can be heated to a condensed sodium is provided. One of the 3 5 temperature above the vaporizing-point of electric terminals is attached to the outer sodium and maintained at such temperature metal casing, as at M, the other leading to the during the operation. rod C as shown at N.

My application filed September 27, 1900, The top of the furnace-chamber is prefer- Serial No. 81,284, is a further division of this ably made separable from the main body of 0 40 application. the furnace and is internally lined with com- In the drawing which shows in central verpacted carbon E and outwardly incased with tical section an electric furnace arranged for an iron shell, a suitable layer of insulating carrying out my present invention, A reprematerial being placed between the cover and sents the furnace-chamber, the Walls of which body of the furnace, as shown in the drawing.

5 are formed of compacted, but porous, carbon The electrode C, passing through the cover of or of hard compacted carbon, in which are arthe furnace, plays in a pipe H, connected to, ranged blocks or masses of porous carbon or but insulated from, the metallic casing of the charcoal permeable to the gases and vapors cover. At the top of the pipeHisastuffing-box evolved in the operation. h, through which the rod-C passes, practically I00 50 B represents the ore charge, hereinafter degas-tight. Although not strictly essential, I scribed. prefer to connect to the upper parts of the pipe H an inlet-pipe g, throughwhi'ch, itfoundn'ecessary or desirable, a small quantityof hydrocarbon gas or gasforming liquid may be passed,the purpose of this being to prevent any small amount of sodium from passing up as vapor around the elect rode and into the upper part of the pipe H and condensing-there. A

"sufficient amount of the hydrocarbon gas can andthe incasing water-jacketto the other circuit-terminah Although'the electric furnace hereinabove described is especially applicable to the reduction: of the'class of compounds above mentioned, of which .alumiuate of sod'a( Na A O is atype, it is applicable to other classespf reactions and to processes where salts are being electrolized,'and I wish it to be fully understood that its application is not limitedt'o the; class of operations herein described.

Taking aluminate of soda typical com-- pound to which my process is applicable, I proceed as follows in carryingout the reduction and process withtthat substance: I take a mixture of aluininate of soda,vwith cokeor carbon, in any form, forming such mixture either by mixing the crushed, ground, or granulated materials'or by forming a mass of sodic aluminate saturated with a hydrocarbon andbaked and, if need he,vcrushed',=or by mixing the aluminate of soda with carbon and coal-tar or pitch or equivalent carbonaceous matter,. itbeing, desirable that the ore charge should not betwo powder-yin consistenc'e, and it being also preferable, except when carbide are being formed, that no eX- cessof carbon above'the amount necessary for the reduction should be employed, since such excess will accumulate in the furnace and-may need to be removed. The charge mixture isfied through the hopper into the furnace in successive portions, regulated", according, to the judgment of the operator, by the temperatureand pressure in the furna'ce. If the ore charge is fed too; slowly, the furnace will become too hot, which will beindicated to the operator not only by the noticeable increase of temperature. of the furnace and the'water discharging from the water-jacket, but also by the diminished amount of carbonic-02nd" passing off. Ift'he charge is fedtoo fast, there will'accu'mulate in the furnace a mass of fused unred uced alumina which will be observed in tapping off from time to time the'c'ont'ents of the furnace. As the ore charge is fed into the fur nace the high temperature causes the sodium 'to distil off rapidly along with the carbonic oxid produced by'the reduction of the o'xid of aluminium, these gaseous products passing passing through the porous carbon Walls of the furnace into the condenser formed by the jacketd,heihgperfectly strained from d ust in their passage through the carbon walls, the vapor of sodium condensing on the outer cooler walls of" the jacket d' and trickling down the same'as aliquid into bottom of the condenser,

from which it is drawn off at proper intervals,

while the carbonic oxid, beingruncondensed, p'asses ofi through the outlet-pipe FL- The t space within the jacketd is kept a-ta tempera- ,ture above96 centi'grad'e, at which temperature sodium is liquid; but by means of the wat er-jacket it is kept below the temperatiire' 3 (red heat) atwhich sodium isvolatile. To better efiect the prevention of'th'e ih'n'erwall of the jacket dfrom rea'chi'n'g too high a temperature, it is advisable that the two walls of the jacket d should be connected ats'ever'al points-by metallic blocksor stays d ,by'whi ch" the temperature of the two walls of the jacket Iwill be more read'il'yand perfectly adjusted and danger of the melting of the inner wall and any possibility of sh'o'rt-ci'rcu iting" aris- .'-ing from' condensed sodium condensing on the inner Walls of the furnace at the jjun'ction of the cover and body-wall or elsewhere is prevented", although suchs'hort-circuit'i ng' could not occur to an ex'tent to' materially eff ;.fect the operation, since th'esodium' in such case would be instantlyvolati lizedby the'heat ofithecurre'nt shunted through it. I evolved in the furnace du'ri'ngth'e operation- {create a pressure within't'he f-urn'ace, which 3 will be indicated to the operator'by'the res- ?sure-gageP', and although there is very little,

The'gases ifi'any; danger of the. ressure reaching a point where any injury to the apparatusconidj -,occnrtherefrom, yet the possibility thereof is fully obviated by previdi'ng" the safetyf valve 0. p This pres's'u re'in' the-furnacemateria'lly assists in driving through the porous :carbon wall of the furnace the vol'at ilized sodium vapor" and the gases evolved in; the I operation. The o'Xi' d of aluminium" left by driving oh the sodium from the. aluminate' is acted upon and reduced by" the carton;

the reactionyielding' jcarbonie' oxid and car bid of "aluminium, the'carbonic oxid passing thr ugh the walls: of the furnace" and the alu mini u'm carbi'd rem ai'n'ing'a'nd acc uni'ulat ing, in the bottom of the furnace, from which 7 it is at suitable in'te'ri' 'a'lstapped ofi'through be prevented. The interior ofthe'furnace'i's i maintai n ed ata very high te m-perature,reaching'incandesce'nce on the'inner surface of the 1 carbonwall and decreasing. to a dull red heat f at the iron casing. By this meanssod'iu'm i's prevented from condensing in the furnace IOO the opening K. By adding through the ore charge or otherwise in reducing it in the furnace a metal lessvolatile than sodium-as,

for instance, iron, copper, or tin-an alloy of the reduced aluminium with such metal is obtained. Further, by addingin the same man ner a volatile metal, such as zinc, there will be obtained in the condenser an alloy of sodium with such other volatile metal. All of such operations and reactions are within the scope of the process which forms the subjectmatter of the present invention." It is also advisable in operating the furnace to heat up the furnace to a high temperature before adding the ore to be reduced, which is readily done by putting in a quantity of granular carbon in the bottom of the furnace to save the carbon lining of the furnace and allowing the are to play thereon, one advantage of which is that by previously raising the furnace to a temperature so high that the ore will reduce rapidly a more perfect operation is secured and the process is rendered more economical. The charge fed into the furnace should be proportionate to the electrical energy delivered to the furnace, the best results being obtained when the electric current and thevfeed of ore are so proportioned that the ore is reduced as fast as fed in and the process conducted in a substantially continuous manner.

By mixing sodium compounds with calcium compounds and the proper proportion of carbon there may be obtained by this process sodium volatilized and condensed in the condenser and calcium carbid remaining in the furnace.

What I claim as my invention, and desire to secure by Letters Patent, is

1. The herein-described electric smelting process formanufacturing metallic sodium and reducing the alumina constituent of sodiuin aluminate, which consists in forming a mixture of sodic aluminate with granular broken or finely-divided carbon, heating said mixture in a tight chamber by heat generated from an electric current, whereby the volatile elementary substance sodium is reduced and passes out of the chamber, condensing the sodium vapor, and tapping or removing from the furnace the reduced product, substantially as set forth.

2. The herein-described electric smelting process for manufacturing metallic sodium and an aluminous product from aluminate of soda, which consists in forming a mixture of sodic aluminate with carbon in a granular, broken or intimately-associated condition in proper proportions, heating said mixture in a tightly closed chamber by heat generated from an electric current, whereby the sodium is reduced, volatilized and passed out of the chamber, the aluminium is reduced from its oxid and combined with carbon, collecting and condensing the sodium vapor, and tapping or removing from the furnace the carbid, substantially as described.

In testimony whereof I hereto aifix my signature in presence of two witnesses.

ALFRED H. OOWLES.

Witnesses:

WM. (1. GILRIE, W. P. DAVISON. 

